This section only provides background information relate to the disclosure, and may not necessarily constitute the prior art.
A conventional check valve includes a valve seat in which a valve hole is formed and a valve disc for opening or closing the valve hole. When a pressure difference across the valve disc is greater than a predetermined value and is directed to open the valve disc in a first direction, the valve disc is opened to allow fluid to flow through the check valve. When the pressure difference across the valve disc is direct towards a second direction opposite to the first direction, the valve disc will never be opened no matter what the value of the pressure difference across the valve disc is, so as to prevent the fluid from flowing in the opposite direction. Such check valve entails a function of allowing fluid to flow in a single direction.
However, in some cases, the check valve is required to be opened not only when the pressure difference in the first direction reaches a first predetermined value, but also when the pressure difference in the second direction reaches a second predetermined value, so as to, for example, achieve pressure relief.
Conventionally, the person skilled in the art uses a solenoid valve and pressure sensors arranged downstream and upstream of the solenoid valve to achieve the above function. However, such arrangement is relatively complex and is expensive.
In view of this, there is a need for a configuration of a valve capable of providing a function of bi-direction flowing of fluid according to a pressure difference across the valve.